<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- 将 obejct 对象中属性是空字符串的替换为 null -->
    <script>
            var obj = {
                name:'小陈',
                age:18,
                reg:'' 
            };
            for(var arr in obj){
                if(obj[arr]==''){
                    obj[arr] = null
                }
            }
            console.log(obj)
</script>
</body>
</html>